China's COVID-19 vaccines using the inactivated virus can be upgraded to enhance its efficacy rate against new variants in about two months, and the procedure won’t be complicated, according to an expert at the Chinese Center for Disease Control and Prevention (CDC).

(File photo: CFP)

Preliminary studies reveal that coronavirus variants initially found in the UK were not able to generate vaccine escape mutants, and it remains to be confirmed whether the vaccine was effective enough against variants found in South Africa and Britain.

Shao Yiming, Chief Expert on AIDS at the Chinese CDC, said in an interview with the Global Times that in the future, if there is a need to upgrade the vaccine to cope with potential escape of the virus, it would take about two months to modify the vaccine for an upgrade to make it more close-fitting against variants. Vaccines using the mRNA technology take a shorter period of time for an upgrade as they don’t require cultivating and inactivating the virus.

As one of the chief medical advisors for R&D of Chinese COVID-19 vaccines, Shao believes there is no need for an immediate upgrade as the current vaccines still provide protection against coronavirus variants.

It should be noted that vaccines neutralize virus strain of the same origin better than that of a different origin, Shao said, adding that the capacity of Chinese vaccines to induce antibodies against virus variants found in Europe, South America and the US in the first half of last year remains stable, but the efficacy rate weakens against the newly emerging variants found in the UK, South Africa and Brazil.

He said whether the difference of data collected in labs will lead to the weakening of protection from vaccines needs to be tested. But the difference shall only be a change in the efficacy rate, but not mean the current vaccine expires. As long as the efficacy rate is within a reasonable range, the vaccine shall remain effective.

As it remains to be seen which coronavirus variant will be the dominant strain and make sure people won’t be infected by another variant, Shao advised that COVID-19 vaccines adopt the models of flu vaccines or HPV vaccines and establish a network to monitor the mutations of the coronavirus strain. By monitoring the mutations, the vaccines can be made into polyvaccines to avoid a pandemic caused by multiple variants at the same time.

(Compiled by Han Xiaomeng)